It has been known a phenomenon in which when a material is irradiated with a light, a different wavelength output light is observed by modulating the original light due to the vibration or rotation of molecules or crystal. This phenomenon is called as Raman effect. The Raman effect is utilized as a method (Raman spectroscopy) to investigate a structure of a state of a molecule and so on as well as an infrared spectroscopy.
However, since the intensity of the Raman scattering light is very weak in comparison with the Rayleigh scattering light which occupies a majority of the scattering light, it has a defect that it is difficult to analyze a molecular structure having a very thin film such as a monomolecular layer formed on a surface on a substrate by the Raman spectroscopy.
For this reason, it has been proposed a surface enhanced Raman spectroscopy analysis (hereinafter, also referred to as SERS) utilizing a surface enhanced Raman spectroscopy. The surface enhanced Raman scattering is a phenomenon in which an intensity of Raman scattering light absorbed on or in a metal such as silver or gold, and the enhancement of an order of 103 to 106, usually. Therefore, the analysis can be performed at high sensitivity and is utilized for the analysis of a mechanism of a chemical reaction on a surface of an electrode (Japanese Patent Publication No. 2005-77362 and Japanese Patent Publication No. 2007-198933).
On the other hand, substrates for surface enhanced Raman spectroscopy analysis have been manufactured and marketed, in which a gold is coated on a nanoprocessed surface of silicone, metal nanoparticles are adhered and fixed on a slide glass, Au nanorod arrays are formed on a slide glass, and so on.
However, the first type such conventional SERS substrates have an enhancement factor of an order of 106 or so at most, their manufacturing method is complicated, and it is unable to reuse by cleaning the surface thereof.